The principal goal for the coming year is to determine whether selective depletion of LH and/or FSH will alter morphological and biochemical parameters in the Sertoli cells. Since FSH has been shown to increase the production of ABP by the Sertoli cells (Hansson et al., Nature New) anti FSH should reverse this condition. Nonconclusive studies have been carried out on the rat testis utilizing antiserum to ovine FSH. Our aim is to use homologous antisera (i.e. antiserum to rat FHS) and to examine: 1. the fine structure of the Sertoli cells; and 2. the levels of ABP and androgens in the rete testis (RTF) after treatment. In addition, the levels of androgens and ABP will be determined in RTF after anti LH treatment. These experiments may also provide important data concerning the hormonal control of the epididymis via luminal androgens.